Identification of parametric ground motion random fields from spatially recorded seismic data     

A. Zerva  J. L. Beck 《地震工程与结构动力学》2003,32(5):771-791

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Optimal location of sensors for reconstruction of seismic responses through spline function interpolation     

M. P. Limongelli 《地震工程与结构动力学》2003,32(7):1055-1074

In this paper, a criterion is proposed for the choice of the optimal location of a limited number of recording sensors for reconstruction of seismic responses of multistorey frames. Reconstruction of unknown responses is performed by modelling through a spline shape function the evolution of the relative acceleration along the height of the building. The coefficients of the spline function are determined by interpolating available responses in terms of absolute accelerations taking into account boundary conditions. The optimal location for a given number of recording sensors is defined as the one corresponding to the minimum value of the global error evaluated on the whole set of reconstructed responses. The criterion has been verified by using simulated responses of numerical models of multistorey frames and responses recorded on real buildings during the Northridge earthquake. A physical characterization of the location of available sensors leading to the minimum global error between calculated and real responses is proposed in terms of effective modal participation factors relevant to the principal modes of the structure. This characterization allows for frames of known modal characteristics the definition of a criterion for the choice of the location of a limited number of sensors for monitoring or vibration control purposes. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

灰色动态组合模型及其在大坝变形预测中的应用   总被引：1，自引：0，他引：1  

田旦  许才军  郭玉斌 《测绘信息与工程》2008,33(6):39-40

提出了先对序列进行平滑处理,再建立灰色动态组合模型,分析了实测数据的计算结果,实现了较高的预测精度。  相似文献   

基于Helmert方差分量估计的Vondrak滤波方法     

钟汉青  曾凡河  周晓卫  丁建勋 《测绘工程》2008,17(3):31-33

从基于Helmert方差分量估计的Vondrak滤波方法（简称HVF法）的基本假设入手,介绍HVF方法,该方法能够在未知拟合函数的情况下,通过自动选择合理的平滑因子控制数据平滑的程度,对时序数据序列进行合理平滑,最大限度地削弱数据序列中的随机误差,将信号与噪声合理分离。  相似文献   

区域高程异常内插方法研究   总被引：1，自引：0，他引：1  

于小平  张廷玉  骆元家  庞贺民  陈增宝 《世界地质》2008,27(4)

在综合利用GPS与水准测量资料的基础上,针对面积较大或地形变化比较复杂的GPS测区,提出了分区拟合转换成正常高的方法.对各种常用拟合模型的适用性进行了分析,并提出了用双三次样条函数或者双三次曲面函数对拟合后的两个小区进行平滑连接,以及相应的算法和精度评定标准0实际算例验证了该方法的可行性,精度可满足四等水准测量的精度要求.  相似文献   

�й���½������GRACE���������仯�о�   总被引：3，自引：2，他引：1  

邹正波  邢乐林  李辉  康开轩  周新 《大地测量与地球动力学》2008,28(1):23-27

??????????GRACE????????????仯??????????? ??GRACE??????λ??????????????????????????????????????????????????й?????????????????仯???????????800 km??????????ó????????????仯?????  相似文献   

Smoothing unit vector fields     

Carlos E. Mendoza 《Mathematical Geology》1986,18(3):307-322

Data, each consisting of a unit vector and a position, are modeled as a smooth unit vector field plus random directional errors; the smooth unit vector field is estimated by fitting a spline to observations. The estimate is nonlinear; it is obtained with an iterative procedure in which, at each step, a least-squares smoothing spline is fitted to a set of pseudovalues. The resulting estimate is exemplified with a data set extracted from the literature in geology. The proposed estimate is compared, using the same data set with that obtained through suggestions of other authors, and is found to have attractive qualities. The use of plots of the resulting estimate to find the appropriate value of the smoothing parameter is emphasized throughout.  相似文献   

基于网格细分技术的三维地质模型光滑方法研究     

屈红刚  潘懋  董攀  柴华  明镜 《地理与地理信息科学》2007,23(6):14-17

针对粗糙的三维地质模型,利用网格细分技术,生成加密光滑的三维模型。分析网格细分技术在三维地质建模中的应用需求以及Loop细分和改进的蝶形细分技术,为保持地质体之间公共面数据的一致性,对"改进的蝶形细分法"做了进一步改进,增加了对边界约束的处理。探讨利用细分技术生成多分辨率模型,通过试验验证了该方法的有效性。  相似文献   

Attenuation effect on seasonal basin-scale water storage changes from GRACE time-variable gravity   总被引：3，自引：0，他引：3  

J. L. Chen  C. R. Wilson  J. S. Famiglietti  Matt Rodell 《Journal of Geodesy》2007,81(4):237-245

In order to effectively recover surface mass or geoid height changes from the gravity recovery and climate experiment (GRACE) time-variable gravity models, spatial smoothing is required to minimize errors from noise. Spatial smoothing, such as Gaussian smoothing, not only reduces the noise but also attenuates the real signals. Here we investigate possible amplitude attenuations and phase changes of seasonal water storage variations in four drainage basins (Amazon, Mississippi, Ganges and Zambezi) using an advanced global land data assimilation system. It appears that Gaussian smoothing significantly affects GRACE-estimated basin-scale seasonal water storage changes, e.g., in the case of 800 km smoothing, annual amplitudes are reduced by about 25–40%, while annual phases are shifted by up to 10°. With these effects restored, GRACE-estimated water storage changes are consistently larger than model estimates, indicating that the land surface model appears to underestimate terrestrial water storage change. Our analysis based on simulation suggests that normalized attenuation effects (from Gaussian smoothing) on seasonal water storage change are relatively insensitive to the magnitude of the true signal. This study provides a numerical approach that can be used to restore seasonal water storage change in the basins from spatially smoothed GRACE data.  相似文献   

Splatting算法在三维CT迭代算法中的应用     

莫会云  潘晋孝 《CT理论与应用研究》2007,16(3):6-12

采用代数重建技术重建三维物体,提出了一种基于splatting原理的ART权值计算方法,以增强重建图像的空间分辨率.该算法基于三维锥束扫描方式,采用双三次样条局部基函数作为插值核,并利用其足印函数对物体进行插值来计算像素的权值.与常量插值相比,这种方法对物体的灰度值有更精确的近似,在相同的实验条件下可重建出分辨率高的物体.给出了适用于三维锥束重建的splatting算法的具体实现,并对实验数据进行了实物重建及误差分析.  相似文献